An incubation experiment was conducted under laboratory condition to study the effect of ordinary super phosphate (OSP) at three different rates (0,30 and 60  kg Pfad.^-1) representing  0,50 and 100% of Recommended Dose (RD), added either singly or combined with various organic manures, i.e. compost (Com) at rates of 10 Mg fad.^-1 (1%) and  20 Mg fad.^-1 (2%),chicken manure  (CM) and Rabbit  manure (RM.) at  rates of 5 Mg fad.^-1 and 10 Mg fad.^-1 representing 0.5 and 1%, respectively, on phosphorus availability in two different soils. Available phosphorus content was determined through different incubation periods i.e., 10, 30, 60, 90 and 120 days using two different soil types, the first was clayey soil, taken from Abu-Hammad, District Sharkia Governorate and the second one was sandy soil collected from the Farm of the Faculty of Agriculture,  El-Khattara County, Sharkia Governorate. The obtained results can be summarized as follows:The values of available phosphorus increased by increasing phosphatic fertilizer rates, which were greater in the clayey soil than in the sandy one. In general available phosphorus values were remarkadly increased after 60 days of incubation for the two investigated soils. The treatment of (50% RD OSP +1% Com. + 1% CM.) as solid form, and (1% Com +0.5% CM +0.5% RM) as liquid form showed more beneficial effect than the treatment of (100% RD OSP) in the case of  clayey soil, while the treatments of (2% Com.) as individual solid phase and (50% RD OSP + 1% Com. + 1% CM.) as liquid phase showed more beneficial effect than the treatment of (100% RD OSP) in a sandy soil. Therefore, the use of half of the recommended dose of phosphatic fertilizer combined with organic manures as solid or liquid phase may reduce the phosphatic fertilizer dose, production cost and consequently environmental pollution.